Clinical symptoms of lumbar spinal stenosis associated with morphological parameters on magnetic resonance images

Abstract

Purpose: This study aimed to investigate the association between the clinical symptoms of central lumbar spinal stenosis (CLSS) and morphological parameters using magnetic resonance imaging (MRI) data.

Methods: We retrospectively reviewed 117 patients who visited our pain clinic from 2009 to 2013 and were diagnosed as CLSS. All patients underwent MRI of the L-spine and we measured the dural sac cross-sectional area (DSA), spinal canal cross-sectional area (SCA), ligamentum flavum cross-sectional area (LFA) and ligamentum flavum thickness (LFT) at the most stenotic intervertebral level on MRI. Clinical outcomes were investigated using the patient-assessed quantitative measurement of visual analog scale (VAS) and subjective disability was assessed by the Oswestry Disability Index (ODI). Additionally, subjective walking distance (SWD) was also collected from electronic medical records.

Results: There were no statistically significant correlations found between the VAS score and the DSA, SCA, LFA, and LFT. A statistically significant linear association existed between the DSA and SCA and the subjective walking distance (r=0.201, P=0.045 and r=0.198, P=0.049, respectively) indicating that the larger the DSA or SCA, the longer the SWD before the occurrence of claudication. The LFA and LFT were significantly correlated with the ODI score (r=0.249, P=0.007 and r=0.250, P=0.007, respectively).

Conclusion: Larger LFA and LFT values are associated with higher ODI values. A larger DSA and SCA are associated with a longer SWD before claudication occurs. To evaluate CLSS patients, clinicians should more carefully inspect the integral morphological parameters than the individual morphological parameters.

Keywords: Ligamentum flavum; Lumbar spinal stenosis; Morphological parameters; Oswestry Disability Index.